Further observations on the sonographic spectrum of gestational trophoblastic disease

Placental morphologic and functional imaging in high-risk pregnancies

The placenta is vital for fetal growth and development. Improvement in ultrasound and magnetic resonance imaging have improved our understanding of placental morphology that can be important as in the case of placental accrete/percreta. Functional imaging is presently mainly performed by the use of Doppler ultrasound and can give information on placental perfusion, which can be vital for clinical diagnosis. This review summarizes the present knowledge on placental imaging and it's clinical value in high-risk pregnancies.

Recognising gestational trophoblastic disease

Gestational trophoblastic disease (GTD) is a group of interrelated tumours originating from the placenta. Hydatidiform molar (HM) pregnancy is the most common form of GTD; this includes both partial hydatidiform molar (PHM) and complete hydatidiform molar (CHM) pregnancies. The importance of such a condition derives from its potential for persistent trophoblastic disease; this is noted to be more common after a CHM (10-20%) compared to a PHM (0.1-11%). The recent routine use of high-resolution trans-vaginal ultrasound (TVS) in early pregnancy has improved the recognition and thus pre-surgical diagnosis of molar pregnancy. Pre-surgical recognition aids planning of surgery, decreases intra-operative complications and identifies women with potential persistent trophoblastic disease. Despite the introduction of TVS, its performance in preoperative diagnosis is quite poor. This is primarily because of the histomorphometric features of the hydropic villi. A significant proportion of HM cases demonstrates minimal hydropic change in the first trimester and therefore is likely to remain unidentifiable by ultrasound examination prior to surgical evacuation, even with improved sonographer expertise. The overall sensitivity for the ultrasound diagnosis of HM is 50-86%. Ultrasound diagnosis of CHM can be made in approximately 80% of the cases, whilst ultrasound diagnosis of PHM is less accurate and nearly 70% of cases will be missed. Correlation of the ultrasonographic findings with human chorionic gonadotropin levels can further improve the recognition of HM pregnancy pre-surgery. Although ultrasound can be helpful in the diagnosis of molar pregnancies, histological confirmation is mandatory. Histological confirmation post-curettage is still the gold standard for the diagnosis of GTD. In this article, we critically evaluate the role of TVS in the pre-surgical recognition of GTD.

Gestational trophoblastic disease: pictorial review

Ultrasound is the modality of choice for evaluating normal or abnormal first trimester pregnancy. Sonography can usually provide a specific diagnosis in abnormal first trimester bleeding. When the sonographic appearance is correlated with the clinical presentation, accurate diagnosis is possible in most cases of gestational trophoblastic disease (GTD). Partial or complete hydatidiform moles can be diagnosed in early gestation. However certain cases will be missed if the curettage material is not sent for pathologic examination. Sometimes molar pregnancies have very unusual sonographic appearances. Sonography and Doppler imaging are helpful in diagnosing gestational trophoblastic disease, in determining whether invasive disease is present, in detecting recurrent disease, and in following the effectiveness of chemotherapy. This pictorial essay describes the pathogenesis, epidemiology, and sonographic spectrum of gestational trophoblastic disease.

The Placenta Revisited: Radiologic–Pathologic Correlation

The placenta is the central support organ for the developing fetus. Recognition of placental variants and insignificant findings is important so as not to suggest an abnormality when one is not present. However, the degree of abnormality, as well as the clinical implications of the findings, must be understood to help guide management of the pregnancy. This article reviews the normal sonographic appearance of the placenta and some anatomic variants, in addition to illustrating various common pathological conditions of the placenta and correlating with gross pathologic and histologic specimens.

Sonographic and Doppler imaging in the diagnosis and treatment of gestational trophoblastic disease: a 12-year experience

OBJECTIVE

To evaluate the clinical utility of sonography with Doppler examination in the diagnosis and treatment of gestational trophoblastic disease (GTD).

METHODS

A retrospective analysis of 355 cases of GTD seen over a 12-year period in 2 large university referral hospitals in China was performed. Clinical appearances, sonographic findings, Doppler waveforms, and patient outcomes were reviewed. Sonographic and Doppler examinations were performed to diagnose the presence of molar tissue, detect invasive disease, assess disease recurrence, and monitor the efficacy of chemotherapy. Doppler waveforms of 13 patients with normal early pregnancies were also examined for comparison.

RESULTS

Of the 355 patients with GTD, 106 had a classic hydatidiform mole (CHM), 33 had a partial hydatidiform mole (PHM), 184 had an invasive hydatidiform mole (IHM), and 32 had choriocarcinoma. Sonography showed abnormal molar tissue confined to the endometrial cavity in all cases of CHM. In cases of IHM and choriocarcinoma, soft tissue invasion and cystic vascular spaces within the myometrium were shown. Cases of PHM had a thickened, hydropic placenta with a concomitant fetus. Doppler waveforms showed resistive indices of 0.55 (SD, 0.06) for CHM, 0.56 (SD, 0.04) for PHM, 0.28 (SD, 0.06) for IHM, 0.25 (SD, 0.05) for choriocarcinoma, and 0.66 (SD, 0.04) for normal pregnancies. The abnormal sonographic and Doppler findings in invasive disease resolved when chemotherapy was successful.

CONCLUSIONS

Sonography and Doppler imaging were helpful in diagnosing GTD, in determining whether invasive disease was present, in detecting recurrence of disease, and in following the effectiveness of chemotherapy.

Doppler study of myometrium in invasive gestational trophoblastic disease

OBJECTIVE

In this prospective study, we aimed to assess the prognostic and diagnostic role of color Doppler flow of myometrium in patients with invasive gestational trophoblastic disease (GTD).

METHODS

Thirty-seven patients, who were enrolled in the study with invasive mole, were assessed with the help of transvaginal color Doppler ultrasound before and after chemotherapy. The place and the size of the myometrial invasions were assessed.

RESULTS

Thirty patients of 37 were treated with the help of single-agent chemotherapy--methotrexate (mtx). In this group, the resistance index (RI) ratios ranged between 0.26 and 0.45 and the size of the myometrial invasion varied between 10 and 50 mm. On the other hand, six patients were treated with mtx and actinomycin D combination and one patient was treated with the help of total abdominal hysterectomy. In this group, the RI ratios ranged between 0.16 and 0.25 and the size of the myometrial invasion varied between 60 and 90 mm. Remission was achieved in all patients.

CONCLUSION

Transvaginal color Doppler study can easily detect invasive GTD. When the depth and the width of the myometrial invasion increase and when there is a low diastolic/systolic ratio, the number of courses and the need for combination of chemotherapy increase.

Sonographic appearance of first trimester complete hydatidiform moles

OBJECTIVE

Complete hydatidiform moles are now being diagnosed earlier in gestation, thus the clinical presentation and pathologic findings of complete molar pregnancy have changed. We studied the sonographic appearance of first trimester moles and the ability of ultrasound to detect them.

METHODS

We reviewed the sonographic interpretation and sonograms, when available, from all patients with first trimester complete moles diagnosed at our institution from January 1988 to March 1996.

RESULTS

Of the 24 patients in our study, the mean gestational age at time of the sonogram was 8.7 +/- 2.0 weeks (mean +/- SD) with a range of 5.7-12.3 weeks. The initial sonographic interpretation was a complete mole in 17 (71%) cases, partial mole versus failed pregnancy in two (8%), and failed pregnancy in five (21%) cases. Of the 22 patients with sonograms available for review, interpretation on review of the images was a complete mole in 18 (82%) cases, partial mole versus failed pregnancy in one (5%), and failed pregnancy in three (14%) cases. The typical sonographic appearance of a first trimester complete mole was a complex, echogenic, intra-uterine mass containing many small cystic spaces.

CONCLUSION

The majority of first trimester complete moles demonstrate a typical ultrasound appearance such that the diagnosis can be made with ultrasound in most cases.

Twin pregnancy with a fetus and a complete hydatidiform mole

Twin pregnancy with a normal fetus and gestational trophoblastic neoplasia as a co-twin is a rare entity. We are reporting such a case and discuss its management.

The role of Doppler sonography in assessment of malignant trophoblastic disease

An observational study on the role of Doppler sonography in the assessment of patients with malignant trophoblastic disease was performed in an Oncology Unit of a University teaching hospital. A total of 32 consecutive patients referred for chemotherapy were recruited. Twenty-three non-pregnant and 18 women in the first trimester of pregnancy acted as controls. The patients were prospectively followed-up for 2 years. It was found that the uterine arterial resistance index and pulsatility index in patients who required chemotherapy were significantly lower when compared with the non-pregnant and pregnant controls; (Student t-test; P < 0.001 and P < 0.01, respectively). Stepwise regression analysis of beta-hCG titres on uterine artery resistance index showed significant correlation, after controlling for uterine volume (adjusted multiple R = 0.71, P < 0.00001). There were, however, no significant independent associations between the initial uterine artery resistance index and the need for chemotherapy, number of courses of chemotherapy required, duration required for the beta-hCG titre to return to normal, presence of metastatic disease, or the subsequent development of drug resistance or relapse. It was concluded that uterine arterial Doppler indices are significantly correlated with trophoblastic activity (beta-hCG titres) in malignant trophoblastic disease. However, their role in the prediction of subsequent tumour behaviour need to be assessed in larger series.

A comparison of colour Doppler sonography and the pelvic arteriogram in assessment of patients with gestational trophoblastic disease

OBJECTIVE

To assess whether colour Doppler sonography can replace pelvic arteriography in the assessment of patients with gestational trophoblastic disease.

DESIGN

An observational study in which patients with gestational trophoblastic disease were assessed with both pelvic arteriography and colour Doppler sonography.

SETTING

The oncology unit of the Department of Obstetrics and Gynaecology, University of Hong Kong. The unit is the main tertiary referral centre for treatment of trophoblastic diseases in Hong Kong.

SUBJECTS

Thirty-two consecutive women referred over an 18 month period.

MAIN OUTCOME MEASURES

The site of localisation of the tumour and the size of the tumour as assessed by both methods.

RESULTS

Eleven patients had a spontaneous fall of beta-hCG titres and did not have pelvic arteriograms performed. The remaining 21 patients had both investigations performed. Four patients had no evidence of abnormal pelvic vessels either on colour Doppler sonography or on pelvic arteriography. Their raised beta hCG titres were due to metastatic disease elsewhere. In the remaining patients the location of the tumour vessels was found to be concordant between the two methods of imaging. Measurements of the mean diameter of tumour bulk by the two methods also agreed well (r = 0.93, P < 0.0001). Pelvic arteriogram over-estimated the size of the tumour in two patients by 2 and 3 cm, respectively, but this did not alter the risk categories of the patients.

CONCLUSION

Colour Doppler sonography is a noninvasive technique that can replace pelvic arteriography in the assessment of patients with trophoblastic diseases.